Apparatus and methods for forming a lateral wellbore

ABSTRACT

A method and system of forming a lateral wellbore in a time and trip saving manner using a mill/drill to locate and place a casing window. In one aspect of the invention, a lateral wellbore is drilled with liner which is subsequently left in the lateral wellbore to line the sides thereof. In another aspect, the mill/drill is rotated with a rotary steerable system and in another aspect, the mill/drill is rotated with a downhole motor or a drill stem.

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent applicationSer. No. 09/848,900, filed May 4, 2001, which claims benefit of U.S.provisional patent application serial No. 60/202,335, filed May 5, 2000,which is herein incorporated by reference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates to methods and apparatus forforming a lateral wellbore in a well, more particularly the inventionrelates to the formation of lateral wellbores with greater efficientlyand with fewer trips into the wellbore.

[0004] 2. Background of the Related Art

[0005] The formation of lateral wellbores from a central cased wellboreis well known in the art. Lateral wellbores are typically formed toaccess an oil bearing formation adjacent the existing wellbore; providea perforated production zone at a desired level; provide cement bondingbetween a small diameter casing and the adjacent formation; or to removea loose joint of surface pipe. Lateral wellbores are advantageousbecause they allow an adjacent area of the formation to be accessedwithout the drilling of a separate wellbore from the surface. Any numberof lateral wellbores may be formed in a well depending upon the needsand goals of the operator and the lateral wellbores can be lined withtubular like the main wellbore of the well from which they are formed.

[0006] The most well known method of forming a lateral wellbore uses adiverter or whipstock which is inserted into the main wellbore and fixedtherein. The whipstock includes a concave, slanted portion which forms asurface for gradually directing a cutting device from the main wellboreof the well towards the wall of the wellbore where the lateral wellborewill be formed. The cutter is fixed at the end of a string of rotatingpipe. Thereafter, an opening or “window” is formed in the wellborecasing as the cutter is guided through the wall by the whipstock.Forming a lateral wellbore with a whipstock assembly typically proceedsas follows: a whipstock assembly including an anchor portion therebelowis lowered into the well to the area below the point where the window isto be formed. The assembly is then fixed in the well with the anchorsecurely held within the wellbore casing. A drill string with a cuttingtool disposed at the end thereof is then lowered into the well and thedrill string and cutter are rotated in order to form the window in thewellbore. In some instances, the drill string and cutter can beinstalled in the well at the same time as the whipstock assembly byattaching the two with a shearable mechanical connection between thewhipstock and the cutter. Thereafter, the cutter and drill string areremoved from the well and the cutter is replaced with a drill bit. Thedrill string and drill bit are then lowered once more into the wellboreand the lateral wellbore is drilled using the conventional drill bit.After the lateral wellbore is formed, it is typically lined with its owncasing which is subsequently cemented in place.

[0007] As the foregoing demonstrates, the formation of a lateralwellbore requires several separate pieces of equipment and moreimportantly, requires several trips into the well to either install orremove the downhole apparatus used to form the window or the lateralwellbore.

[0008] There are a number of apparatus currently available which, aredesigned to simplify or save time when performing operations in awellbore. For example, a “mill/drill” is a special bit specificallydesigned to both mill through a casing and drill into a formation. Useof a mill/drill can eliminate the use of a separate mill and drill bitin a lateral wellbore operation and therefore eliminate the need to pullthe mill out of the wellbore after forming the window in order toinstall the drill bit to form the lateral wellbore. Typically, themill/drill includes materials of different physical characteristicsdesigned to cut either the metallic material of the wellbore casing toform a window or designed to cut rock in formation material as thelateral wellbore is formed. In one example, inserts are installed in thedrill bit whereby one set of inserts includes a durable cuttingstructure such as tungsten carbide for contacting and forming the windowin the wellbore casing and a second set of inserts is formed of a hardermaterial better suited for drilling through a subterranean formation,especially a rock formation. The first cutting structure is positionedoutwardly relative to the second cutting structure so that the firstcutting structure will mill through the metal casing while shielding thesecond cutting structure from contact with the casing. The first cuttingstructure can wear away while milling through the casing and uponinitial contact with the rock formation, thereby exposing the secondcutting structure to contact the rock formation. Combination milling anddrill bits such as the foregoing are described in U.S. Pat. Nos.5,979,571 and 5,887,668 and those patents are incorporated herein byreference in their entirety.

[0009] Another recent time saving improvement for downhole oil welloperations involves the drilling of a wellbore using the tubular, orliner which will subsequently form the casing of the wellbore. Thismethod of “drilling with liner” avoids the subsequent procedure ofinserting liner into a previously drilled wellbore. In its simplestform, a drill bit is disposed at the end of a tubular that is of asufficient diameter to line the wall of the borehole being formed by thedrill at the end thereof. Once the borehole has been formed and theliner is ready to be cemented in the borehole, the drill bit at the endthereof is either removed or simply destroyed by the drilling of asubsequent, smaller diameter borehole.

[0010] Drilling with liner can typically be performed two ways: In thefirst method, the liner string itself with the drill bit fixed at theend thereof rotates. In a second method, the liner string isnon-rotating and the drill bit, disposed at the end of the liner stringand rotationally independent thereof, is rotated by a downhole motor orby another smaller diameter drill stem disposed within the liner thatextends back and is rotated from the surface. In one example of anon-rotating liner, the bit includes radially extendable and retractablearms which extend outwards to a diameter greater than the tubular duringdrilling but are retractable through the inside diameter of the tubularwhereby, when the wellbore is completed, the bit can be completelyremoved from the wellbore using a wireline device. The foregoingarrangement is described in U.S. Pat. No. 5,271,472 and that referenceis incorporated herein in its entirety.

[0011] In another example of drilling with liner, a non-rotating tubularis used with a two-part bit having a portion rotating within the end ofthe tubular and another portion rotating around the outer diameter ofthe tubular. The rotation of each portion of the bit is made possibleeither by a downhole motor or by rotational force supplied to a separatedrill stem from the surface of the well. In either case, the centralportion of the bit can be removed after the wellbore has been formed.The liner remains in the wellbore to be cemented therein. A similararrangement is described in U.S. Pat. No. 5,472,057 and that patent isincorporated herein by reference in its entirety.

[0012] Yet another emerging technology offering a savings of time andexpense in drilling and creating wellbores, relates to rotary steerabledrilling systems. These systems allow the direction of a wellbore to bechanged in a predetermined manner as the wellbore is being formed. Forexample, in one well-known arrangement, a downhole motor having a jointwithin the motor housing can create a slight deviation in the directionof the wellbore as it is being drilled. Fluid-powered motors have beenin use in drilling assemblies in the past. These designs typicallyutilize a fixed stator and a rotating rotor, which are powered by fluidflow based on the original principles developed by Moineau. Typical ofsuch single-rotor, progressive cavity downhole motor designs used indrilling are U.S. Pat. Nos. 4,711,006 and 4,397,619, incorporated hereinin their entirety. The stator in Moineau motors is built out of elasticmaterial like rubber. Other designs have put single-rotor downhole powersections in several components in series, with each stage using a rotorconnected to the rotor of the next stage. Typical of these designs areU.S. Pat. Nos. 4,011,917 and 4,764,094, incorporated herein in theirentirety.

[0013] Another means of directional drilling includes the use rotarysteerable drilling units with hydraulically operated pads formed on theexterior of a housing near the drill bit. The mechanism relies upon aMWD device (measuring while drilling) to sense gravity and use themagnetic fields of the earth. The pads are able to extend axially toprovide a bias against the wall of a borehole or wellbore and therebyinfluence the direction of the drilling bit therebelow. Rotary steerabledrilling is described in U.S. Pat. Nos. 5,553,679, 5,706,905 and5,520,255 and those patents are incorporated herein by reference intheir entirety.

[0014] Technology also exists for the expansion of tubulars in awellbore whereby a tubular of a first diameter may be inserted into awellbore and later expanded to a greater inside and outside diameter byan expansion tool run into the wellbore on a run-in string. Theexpansion tool is typically hydraulically powered and exerts a force onthe inner surface of the tubular when actuated.

[0015]FIGS. 1 and 2 are perspective views of the expansion tool 100 andFIG. 3 is an exploded view thereof. The expansion tool 100 has a body102 which is hollow and generally tubular with connectors 104 and 106for connection to other components (not shown) of a downhole assembly.The connectors 104 and 106 are of a reduced diameter (compared to theoutside diameter of the longitudinally central body part 108 of the tool100), and together with three longitudinal flutes 110 on the centralbody part 108, allow the passage of fluids between the outside of thetool 100 and the interior of a tubular therearound (not shown). Thecentral body part 108 has three lands 112 defined between the threeflutes 110, each land 112 being formed with a respective recess 114 tohold a respective roller 116. Each of the recesses 114 has parallelsides and extends radially from the radially perforated tubular core 115of the tool 100 to the exterior of the respective land 112. Each of themutually identical rollers 116 is near-cylindrical and slightlybarreled. Each of the rollers 116 is mounted by means of a bearing 118at each end of the respective roller for rotation about a respectiverotational axis which is parallel to the longitudinal axis of the tool100 and radially offset therefrom at 120-degree mutual circumferentialseparations around the central body 108. The bearings 118 are formed asintegral end members of radially slidable pistons 120, one piston 120being slideably sealed within each radially extended recess 114. Theinner end of each piston 120 (FIG. 3) is exposed to the pressure offluid within the hollow core of the tool 100 by way of the radialperforations in the tubular core 115. In the embodiment shown in FIGS.1-3, the expander tool is designed to be inserted in a tubular string.It can however, also be used at the end of a tubular string with fluidpassing through it via ports formed in its lower end.

[0016] After a predetermined section of the tubular has been expanded toa greater diameter, the expansion tool can be deactivated and removedfrom the wellbore. Methods for expanding tubulars in a wellbore aredescribed and claimed in Publication No. PCT/GB99/04225 and thatpublication is incorporated by reference in its entirety herein.

[0017] There is a need therefore for methods and apparatus for forming alateral wellbore whereby subsequent trips into the main wellbore areminimized and wherein the wellbore can be formed in a faster, moreefficient manner utilizing less time, equipment and personnel. There isa further need for a method of forming a lateral wellbore which utilizesvarious apparatus which have been developed for unrelated activities ina wellbore.

SUMMARY OF THE INVENTION

[0018] The present invention generally provides a method and system ofcoupling a steerable system, such as a rotary steerable system, to amill/drill to drill a lateral wellbore. The mill/drill is suitable formilling through a casing, such as a steel casing, and drilling throughan underground formation. The method and system can include a diverter,such as a whipstock, for directing the mill/drill toward the casing onthe wellbore.

[0019] In one aspect, a method of drilling a lateral hole with a lineris provided, comprising inserting a liner coupled to a rotary steerablesystem and a mill/drill into a wellbore having a casing disposedtherein, directing the mill/drill toward a wall of the casing, cutting awindow in the casing with the mill/drill, drilling into a formationusing the mill/drill to form a lateral hole while advancing the linerattached to the mill/drill into the lateral hole, and leaving at least aportion of the liner in the lateral hole after the lateral hole isdrilled. In another aspect, method of drilling a lateral with a liner isprovided, comprising inserting a liner coupled to a mill/drill into awellbore having a casing inserted therein, directing the mill/drilltoward a wall of the casing, cutting a window in the casing with themill/drill, drilling into a formation using the mill/drill to form alateral hole while advancing the liner attached to the mill/drill intothe lateral hole, and leaving at least a portion of the liner in thelateral hole after the lateral hole is drilled. In another aspect, amethod of drilling a lateral hole in a wellbore is provided, comprisinginserting a rotary steerable system coupled to a mill/drill into awellbore, the wellbore having a casing inserted therein, directing themill/drill toward a wall of the casing, cutting a window in the casingwith the mill/drill, and drilling into a formation using the mill/drillto form a lateral hole while advancing the rotary steerable systemattached to the mill/drill into the lateral.

[0020] In another aspect, a system for drilling a lateral hole in awellbore is provided, comprising a means for inserting a rotarysteerable system attached to a mill/drill into a wellbore having acasing disposed therein, a means for directing the mill/drill toward awall of the casing, a means for cutting a window in the casing with themill/drill, a means for drilling into a formation using the mill/drillto form a lateral hole while advancing the rotary steerable system intothe lateral hole, and a means for leaving at least a portion of therotary steerable system in the lateral hole after the lateral hole isdrilled. Further, in another aspect, a system for drilling a lateralhole in a wellbore is provided, comprising a means for inserting a linerattached to a mill/drill into a wellbore having a casing insertedtherein, a means for directing the mill/drill toward a wall of thecasing, a means for cutting a window in the casing with the mill/drill,a means for drilling into a formation using the mill/drill to form alateral hole while advancing the liner attached to the mill/drill intothe lateral hole, and a means for leaving at least a portion of theliner in the lateral hole after the lateral hole is drilled.

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] So that the manner in which the above recited features,advantages and objects of the present invention are attained and can beunderstood in detail, a more particular description of the invention,briefly summarized above, may be had by reference to the embodimentsthereof which are illustrated in the appended drawings.

[0022] It is to be noted, however, that the appended drawings illustrateonly typical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

[0023]FIG. 1 is a perspective view of an expansion tool.

[0024]FIG. 2 is a perspective end view in section thereof.

[0025]FIG. 3 is an exploded view of the expansion tool.

[0026]FIG. 4A is a section view of a cased wellbore having a linerinserted therein with a mill/drill disposed on the end thereof, themill/drill connected by a shearable connection to a whipstock and anchorassembly therebelow.

[0027]FIG. 4B is a section view of a wellbore illustrating a windowformed in the wellbore casing by the rotating liner and the mill/drill.

[0028]FIG. 4C is a section view of a wellbore depicting a lateralwellbore having been formed and the liner having lined the interiorthereof.

[0029]FIG. 5A is a section view of a wellbore with a liner therein andan independently rotating, two-part mill/drill disposed thereupon,rotation of the mill/drill provided by a motor thereabove.

[0030]FIG. 5B is a section view of a wellbore with a liner therein andan independently rotating two-part mill/drill disposed thereupon.

[0031]FIG. 6A is a section view of a wellbore with a selective expansiontool disposed therein.

[0032]FIG. 6B is a section view of the wellbore with the liner havingbeen expanded into and sealing the window of the well casing.

[0033]FIG. 7A is a section view of a wellbore having a drill stem with aMWD device, rotary steerable mechanism and a mill/drill disposedthereon.

[0034]FIG. 7B is a section view of a wellbore illustrating the rotarysteerable mechanism having biased the mill/drill to form a window in thecasing wall of the wellbore.

[0035]FIG. 8 is a section view of a wellbore showing a non-rotating,bent liner with a rotationally independent, two-piece mill/drilldisposed thereon.

[0036]FIG. 9 is a section view of a wellbore with a rotating linerdisposed therein, the rotating liner having a rotary steerable unit anda mill/drill disposed at the end thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

[0037]FIG. 4A is a section view of a cased wellbore 10 having a liner 15disposed therein and a mill/drill 20 disposed at the end thereof. Ashearable connection 25 between the mill/drill and a diverter, in thiscase a whipstock 30, therebelow allows the entire assembly, including ananchor 35, to be run into the wellbore at once. The anchor 35 is locatedbelow the whipstock and fixes the whipstock in place allowing themill/drill 20 to form a window at a predetermined point in the wall ofthe casing 40 as it rotates along a concave portion 42 of the whipstock30. After the assembly is run into the wellbore and the whipstock 30 andanchor 35 are fixed in place, a downward force is applied to the liner15 and mill/drill 20 to cause the shearable connection 25 between themill/drill and the whipstock to fail. The mill/drill can then be rotatedand formation of the window can begin. In the embodiment shown in FIG.4A, the mill/drill 20 is rotationally fixed to the end of the liner 15and rotational force is applied to the liner at the well surface.

[0038]FIG. 4B is a section view of the wellbore illustrating a window 45that has been formed in the casing wall 40 by the rotating mill/drill20. FIG. 4B also illustrates the liner 15 having advanced through thewindow 45 and into the lateral wellbore. FIG. 4C, a section view of thewellbore 10, shows the lateral wellbore 50 formed and lined with theliner 15 which was inserted into the lateral wellbore as it was formed.In the embodiment illustrated, the mill/drill 20 remains at the end ofthe liner 15 after the lateral wellbore 50 is formed and can besubsequently destroyed by additional drilling. To complete the lateralwellbore, portions of the liner extending into the central wellbore fromthe window may be removed. Techniques for cutting off that portion of aliner extending into and blocking a vertical wellbore are described inU.S. Pat. Nos. 5,301,760 and 5,322,127 and those patents areincorporated herein by reference in their entirety.

[0039] In an alternative embodiment of the arrangement depicted in FIGS.4A-C, the liner 15 with the mill/drill disposed thereupon can benon-rotating and a two-piece drill/mill 55 rotates independently of theliner 15 with rotational forces supplied by a downhole motor within theliner or by a rotational device located at the surface of the well. Forexample, FIG. 5A is a section view of a two-piece mill/drill 55 withrotational force provided thereto by a downhole motor 60 and FIG. 5B isa view of the two-piece mill/drill 55 with rotational force providedfrom the well surface (not shown). A first portion 65 of the two-piecemill/drill 55 has an outer diameter smaller than the inside diameter ofthe liner and a second portion 70 of the mill/drill 55 extends aroundthe perimeter of the liner and is rotationably coupled to the firstportion 65. After the lateral wellbore has been formed, the portions 65,70 of the mill/drill 55 can be disconnected from each other and thefirst portion 65 may be removed from the lateral wellbore with awireline or any other well-known technique for recovering downholedevices from a wellbore.

[0040] When drilling a lateral wellbore with liner, undersized liner maybe used during the formation of the lateral wellbore to facilitate theoperation and thereafter, when the wellbore is formed, the liner can beexpanded to increase its diameter to more closely match the insidediameter of the lateral wellbore. Enlargement of the liner is typicallyaccomplished by insertion of a selective expansion device into thelateral wellbore and subsequent actuation of the device which places anoutward force on the wall of the liner. Moving the actuated deviceaxially in the liner creates a section of enlarged liner. FIG. 6A is asection view of a lateral wellbore 10 drilled with liner 300 and havinga selective expansion tool 310 inserted therein on a separate tubularstring 312 for enlarging the diameter of the liner. In the figure, theselective expansion tool 310 is run into the lateral wellbore where itis then actuated and urged towards the window 315 of the wellbore,enlarging the liner to a size adequate to line the lateral wellbore forcementing therein. Compliant rollers 116 (FIG. 1) of the expansion tool310 may alternatively be cone-shaped to facilitate a gradual enlargementof the liner as the expansion tool moves therethrough. In FIG. 6B,another section view of a lateral wellbore 10, the undersized liner 312has been expanded up to and through the window in the vertical casing ina manner that has sealed an annular area 320 between the exterior of theliner and the window opening. After removal of the selective expansiontool 310, the liner 312 can be severed at the window leaving a sealedlateral wellbore extending from the central wellbore.

[0041]FIG. 7A is a section view of a wellbore 10 having a conventionaldrill stem 75 for providing rotational force to a mill/drill 78 disposedat the end thereof. A rotary steerable mechanism 80 is installed abovethe mill/drill and includes selectively radially extendable pads 85which can transmit a force against the casing wall causing themill/drill therebelow to be diverted towards the opposite wall of thecasing. A measurement while drilling device (MWD) 90 is installed withinthe tubular string to provide orientation.

[0042] As illustrated in FIG. 7B, the assembly including the MWD 90,steerable mechanism 80 and mill/drill 78 is run into the wellbore 10 toa predetermined depth and, thereafter, at least one pad 85 of the rotarysteerable mechanism 80 is actuated to urge the mill/drill 78 againstthat area of the casing wall 87 where the window will be formed. Afterthe window has been formed by the mill/drill 78, the assembly extendsinto the window and the lateral wellbore is formed. Upon completion ofthe lateral wellbore the assembly is removed from the well and the newlateral wellbore may be lined with tubular liner in a conventionalmanner well known in the art.

[0043]FIG. 8 is a section view of a wellbore 10 wherein a liner 100 isprovided with a two-piece mill/drill 105 disposed at the end thereof,the liner having a bent portion 115 at the lower end which directs themill/drill 105 to a predetermined area of the wellbore casing 120 wherea window will be formed. In this embodiment, the liner is non-rotatingand the mill/drill 105 rotates independently thereof, powered by eithera downhole motor 110 thereabove or a rotary unit located at the surfaceof the well (not shown). To cooperate with the bent liner portion,downhole motor 110 may have a bent housing. As described herein, themill/drill is a two-piece assembly with a center portion 107 that can beremoved when the formation of the lateral wellbore is complete.

[0044] In another embodiment depicted in FIG. 9, a non-rotating straightliner 200 is provided with a rotary steerable mechanism 205 and amill/drill 210 disposed at a lower end thereof. The mill/drill 210rotates independently of the non-rotating liner and is powered eitherwith a downhole motor disposed within the liner in a separate string ora rotating unit at the surface of the well. The rotary steerablemechanism 205, like those described herein has selectively extendablepads 207 which exert a force against the casing wall 120, of the centralwellbore, biasing the mill/drill 210 therebelow in a direction where thewindow is to be formed in the casing wall and formation of the lateralwellbore is to begin

[0045] In this embodiment, the assembly is lowered into the well to apredetermined depth and thereafter, the 200 liner and mill/drill 210rotate as the mill/drill 210 is urged against the wall of the casing 220biased by the rotary steerable mechanism 207. The mill/drill 210 forms awindow in the casing and then the assembly, including the rotating liner200, is urged through the window and the lateral wellbore is formed.After the wellbore is formed, an MWD device (not shown) which is locatedon a separate tubular string within the liner is removed and the fixedmill/drill is left in the lateral wellbore.

[0046] While foregoing is directed to the preferred embodiment of thepresent invention, other and further embodiments of the invention may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

1. A method of using a liner to drill a lateral wellbore of a well,comprising: a) inserting the liner having a mill/drill disposed at oneend into a wellbore having a wall therein; b) directing the mill/drilltowards a pre-selected area of the wall; c) cutting an opening in thewall with the mill/drill; d) drilling into a formation proximate theopening while advancing the liner to form the lateral wellbore; and e)leaving at least a portion of the liner in the lateral wellbore.
 2. Themethod of claim 1, wherein the wall is cased with a casing.
 3. Themethod of claim 1, wherein the liner and the mill/drill are rotationallycoupled.
 4. The method of claim 1, wherein the liner and mill/drill arerotationally independent and rotation of the mill/drill is provided by adownhole motor disposed thereabove.
 5. The method of claim 1, whereinthe mill/drill comprises an inner portion and an outer portion, theinner portion being selectively removable from the outer portion of themill/drill.
 6. The method claim 5, further comprising: a) removing atleast one portion of the mill/drill; b) replacing the portion of themill/drill; c) inserting the replaced portion in the liner; and d)continuing to advance the liner.
 7. The method of claim 1, wherein therotation of the mill/drill is provided by a rotational force at asurface of the well.
 8. The method of claim 1, wherein directing themill/drill towards the pre-selected area of the wall is performed by adiverter fixed in the wellbore there below.
 9. The method of claim 8,wherein directing the mill/drill toward the wall comprises: a)selectively coupling the diverter to the mill/drill; b) fixing thediverter at a predetermined location in the wellbore; c) disengaging thecoupling between the diverter and the mill/drill; d) diverting themill/drill along a slanted surface of the diverter toward the wall tocut the opening.
 10. The method of claim 1, further comprising removingat least a portion of the liner extending into the wellbore from theopening.
 11. The method of claim 1, further comprising expanding atleast a portion of the liner within the lateral wellbore.
 12. The methodof claim 11, wherein the liner is expanded into a contactingrelationship with the opening.
 13. The method of claim 12, wherein theliner is expanded into a sealing relationship with the opening.
 14. Themethod of claim 1, further comprising directing the mill/drill by usinga bent liner.
 15. A method of drilling a lateral wellbore in a wellbore,comprising: a) inserting a rotary steerable system coupled to amill/drill into a wellbore having a wall therein; b) directing themill/drill towards a pre-selected area of the wall; c) cutting anopening in the wall with the mill/drill; and d) drilling into aformation proximate the opening while advancing the rotary steerablesystem to form the lateral wellbore.
 16. The method of claim 15, furthercomprising coupling the rotary steerable system and mill/drill to aliner and leaving at least a portion of the liner in the lateralwellbore after the lateral wellbore is drilled.
 17. The method of claim16, wherein the liner and the mill/drill are rotationally coupled. 18.The method of claim 16, further comprising removing at least a portionof the liner extending into the wellbore from the opening.
 19. Themethod of claim 15, wherein directing the mill/drill toward the wallcomprises using a diverter.
 20. A method of using a liner to drill alateral wellbore, comprising: a) inserting the liner coupled to a rotarysteerable system and a mill/drill into a wellbore having a wall therein;b) directing the mill/drill towards a pre-selected area of the wall; c)cutting an opening in the wall with the mill/drill; d) drilling into aformation proximate the opening while advancing the liner to form thelateral wellbore; and e) leaving at least a portion of the liner in thelateral wellbore after the lateral wellbore is drilled.